Air turbine starter with lubrication recirculation circuit

ABSTRACT

An air turbine starter (ATS) for a gas turbine engine having an accessory gear box (AGB) with a lubricant reservoir, the air turbine starter comprising a housing at least partially defining a working air flow path; a turbine section comprising a turbine having an output shaft and a plurality of blades circumferential spaced about the output shaft and at least partially extending into the working air flow path; a drive section having a drive shaft operably coupled to the output shaft to engage the AGB; and a lubrication recirculation circuit fluidly coupled to the lubricant reservoir.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to IN Patent Application No.202211039930 filed Jul. 12, 2022, which is incorporated herein in itsentirety.

TECHNICAL FIELD

The present subject matter relates generally to an air turbine starter,and more specifically to lubricant distribution within the air turbinestarter.

BACKGROUND

An aircraft engine, for example a gas turbine engine, is engaged inregular operation to an air turbine starter. The internal components ofthe air turbine starter require lubrication. The supply of lubricant,such as oil, to the air turbine starter can be self-contained orprovided from the accessory gear box.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic illustration of a gas turbine engine with an airturbine starter in accordance with various aspects described herein.

FIG. 2 is a sectional view of the air turbine starter with a lubricationrecirculation circuit according to various aspects described herein.

FIG. 3 is a schematic of a lubrication recirculation circuit for the airturbine starter of FIG. 2 according to an aspect of the disclosureherein.

FIG. 4 is a method of supplying lubrication to the air turbine starterof FIG. 2 according to an aspect of the disclosure herein.

FIG. 5 is a sectional view along line V-V of FIG. 2 of a lubricationrecirculation circuit for the air turbine starter with a valve in aturbine supply position according to an aspect of the disclosure herein.

FIG. 6 is the lubrication recirculation circuit of FIG. 5 with the valvein a drive supply position according to another aspect of the disclosureherein.

FIG. 7 is the lubrication recirculation circuit of FIG. 5 with the valvein a bypass position according to another aspect of the disclosureherein.

FIG. 8 is an enlarged view of a portion of the air turbine starter fromFIG. 2 according to a variation of the air turbine starter with alubricant diverter.

FIG. 9 is an enlarged view of a portion of the air turbine starter fromFIG. 2 according to a variation of the air turbine starter with a set ofsuction inlets.

FIG. 10 is an enlarged view of a portion of the air turbine starter FIG.2 according to a variation of the air turbine starter with a lubricantdiverter.

DETAILED DESCRIPTION

The present disclosure is related to a lubrication recirculation circuitin an air turbine starter. In one non-limiting example the lubricationrecirculation circuit includes an accessory gear box (AGB) and an airturbine starter (ATS) where lubrication, in some cases oil, is sharedbetween the two. The lubrication recirculation circuit can operate underdifferent operating conditions and can include a bypass to the AGB. Thestarter can have various applications including starting a gas turbineengine and generating electrical power when the gas turbine engine is inoperation. While the exemplary embodiment described herein is directedto a starter and AGB, embodiments of the disclosure can be applied toany implementation of a lubrication recirculation circuit shared betweentwo engine components.

The word “exemplary” may be used herein to mean “serving as an example,instance, or illustration.” Any implementation described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other implementations. Additionally, unlessspecifically identified otherwise, all embodiments described hereinshould be considered exemplary.

As used herein, the terms “first”, “second”, and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.

The terms “forward” and “aft” may be used herein to refer to relativepositions within a gas turbine engine or vehicle, and refer to thenormal operational attitude of the gas turbine engine or vehicle. Forexample, with regard to a gas turbine engine, forward refers to aposition closer to an engine inlet and aft refers to a position closerto an engine nozzle or exhaust.

As used herein, the term “upstream” may be used herein to refer to adirection that is opposite the lubricant flow direction, and the term“downstream” refers to a direction that is in the same direction as thelubricant flow. The term “fore” or “forward” means in front of somethingand “aft” or “rearward” means behind something. For example, when usedin terms of lubricant flow, fore/forward can mean upstream andaft/rearward can mean downstream. These terms may also be used todescribe relative location.

Additionally, as used herein, the terms “radial” or “radially” refer toa direction away from a common center. For example, in the overallcontext of a turbine engine, radial refers to a direction along a rayextending between a center longitudinal axis of the engine and an outerengine circumference.

All directional references (e.g., radial, axial, proximal, distal,upper, lower, upward, downward, left, right, lateral, front, back, top,bottom, above, below, vertical, horizontal, clockwise, counterclockwise,upstream, downstream, forward, aft, etc.) are only used foridentification purposes to aid the reader's understanding of the presentdisclosure, and do not create limitations, particularly as to theposition, orientation, or use of aspects of the disclosure describedherein. Connection references (e.g., attached, coupled, connected, andjoined) are to be construed broadly and can include intermediatestructural elements between a collection of elements and relativemovement between elements unless otherwise indicated. As such,connection references do not necessarily infer that two elements aredirectly connected and in fixed relation to one another. The exemplarydrawings are for purposes of illustration only the dimensions,positions, order and relative sizes reflected in the drawings attachedhereto can vary.

The singular forms “a”, “an”, and “the” include plural references unlessthe context clearly dictates otherwise. Furthermore, as used herein, theterm “set” or a “set” of elements can be any number of elements,including only one.

Approximating language, may be used herein throughout the specificationand claims, is applied to modify any quantitative representation thatcould permissibly vary without resulting in a change in the basicfunction to which it is related. Accordingly, a value modified by a termor terms, such as “about”, “approximately”, “generally”, and“substantially”, are not to be limited to the precise value specified.In at least some instances, the approximating language may correspond tothe precision of an instrument for measuring the value, or the precisionof the methods or machines for constructing or manufacturing thecomponents and/or circuits. In at least some instances, theapproximating language may correspond to the precision of an instrumentfor measuring the value, or the precision of the methods or machines forconstructing or manufacturing the components and/or circuits. Forexample, the approximating language may refer to being within a 1, 2, 4,5, 10, 15, or 20 percent margin in either individual values, range(s) ofvalues and/or endpoints defining range(s) of values. Here and throughoutthe specification and claims, range limitations are combined andinterchanged, such ranges are identified and include all the sub-rangescontained therein unless context or language indicates otherwise. Forexample, all ranges disclosed herein are inclusive of the endpoints, andthe endpoints are independently combinable with each other.

“Proximate” may be used herein is not limiting, rather a descriptor forlocating parts described herein. Further, the term “proximate” meansnearer or closer to the part recited than the following part. Forexample, where a first hole and a second hole are located at a distancefrom a wall, where the first hole is proximate the wall, the first holeis closer to the wall than the second hole.

Referring to FIG. 1 , a gas turbine engine 10 having a compressorsection 12, a combustion section 14, and a turbine section 16 isillustrated. An air intake 18 defined by a fan 20 supplies air to thecompressor section 12 of the engine 10. The air intake 18 and thecompressor section 12 are collectively known as the ‘cold section’ 22 ofthe gas turbine engine 10 located upstream from the combustion section14. The compressor section 12 provides the combustion section 14 withhigh-pressure air. The high-pressure air is mixed with fuel andcombusted in a combustion chamber (not shown) in the combustion section14 to form hot and pressurized combusted gasses. The hot and pressurizedcombusted gasses pass through the turbine section 16 before exhaustingfrom the gas turbine engine 10. As the pressurized gasses pass through ahigh-pressure turbine (not shown) and a low-pressure turbine (not shown)of the turbine section 16, the turbines extract rotational energy fromthe flow of the gases passing through the gas turbine engine 10. Thecompressor section 12 and the turbine section 16 can be coupled to eachother by way of a shaft to power the compressor section 12. Thelow-pressure turbine can be coupled to the fan 20 of the air intake 18by way of a shaft to power the fan 20.

The gas turbine engine 10 can be a turbofan engine commonly used inmodern commercial and military aviation or it could be a variety ofother known gas turbine engines such as a turboprop or turboshaft. Thegas turbine engine 10 can also have an afterburner that burns anadditional amount of fuel downstream from the turbine section 16 toincrease the velocity of the exhausted gases, and thereby increasingthrust.

A starter motor or an air turbine starter (ATS) 100 can be drivinglycoupled to the gas turbine engine via an accessory gear box (AGB) 102,also known as a transmission housing, schematically illustrated as beingmounted to the gas turbine engine 10. A horizontal drive shaft 104 canextend from the AGB 102 to a transfer gear box 106. The AGB 102 can becoupled to a turbine shaft within the gas turbine engine 10, either tothe low-pressure or high-pressure turbine by way of a radial drive shaft(not shown) extending from the transfer gear box 106 into the gasturbine engine 10.

Referring now to FIG. 2 , the ATS 100 is shown in greater detail. TheATS 100 can include an ATS turbine section 107 including a turbinehousing 108 defining an inlet 110 and an outlet 112 and a turbinesection interior 164. A flow path 114 can extend between the inlet 110and outlet 112 for communicating a flow of gas from the inlet 110 to theoutlet 112. A turbine member 116 can include a turbine shaft 118 and aplurality of blades 120 extending from the turbine shaft 118. Theturbine shaft 118 can be journaled within the turbine housing 108. Theplurality of blades 120 can be disposed within the flow path 114 forrotatably extracting mechanical power from the flow of gas along theflow path 114.

A drive housing 122 can define a drive section 123 with at least aportion of a gear box 124 defining a drive section interior 166. A geartrain 126 can be disposed within the gear box 124 and be drivinglycoupled with the turbine shaft 118. The gear train 126 can include aring gear 128 and can further comprise any gear assembly including forexample but not limited to a planetary gear assembly or a pinion gearassembly. The turbine shaft 118 can be rotatably mounted to the geartrain 126 allowing for the transfer of mechanical power from the turbinemember 116 to the gear train 126. The turbine shaft 118 can be supportedby a pair of turbine bearings 130.

A carrier member 131 can be drivingly coupled with the gear train 126. Adriven member 132 can include a drive shaft 134 and be rotatably mountedto the carrier member 131. An aperture 136 in the carrier member 131 canreceive the drive shaft 134. The carrier member 131 can be supported bycarrier bearings 138.

The turbine section interior 164 and the drive section interior 166together define a housing interior 140. The housing interior 140 cancontain lubricant, by way of non-limiting example oil, to providelubrication and cooling to at least one lubricated component 141, i.e.mechanical parts contained within such as the gear train 126, ring gear128, and bearings 130, 138.

A clutch 142 can be mounted to the carrier member 131. The driven member132 is coupled to the clutch 142 and additionally supported by drivebearings 143. The driven member 132 is driven by the carrier member 131which in turn is driven by the gear train 126 which in turn is driven bythe turbine member 116. The clutch 142 can be any type of shaftinterface portion that forms a single rotatable shaft 144 comprising theturbine member 116, the carrier member 131, and the driven member 132.The shaft interface portion can be by any known method of couplingincluding, but not limited to, gears, splines, a clutch mechanism, orcombinations thereof.

A decoupler assembly 148 can be disposed within at least a portion ofthe driven member 132. An output shaft 149 can be mounted to the driveshaft 134. The output shaft 149 can be operably coupled to the AGB 102which in turn is operably coupled to the engine 10.

A lubrication recirculation circuit (LRC) 150 can be at least partiallydisposed within the drive housing 122. The LRC 150 can include alubrication line 152 extending between the AGB 102 and the housinginterior 140. The LRC 150 can further include a set of AGB outlets 153fluidly coupled to the housing interior 140. After passing through theLRC 150, the set of AGB outlets 153 provide an exit for lubricant fromthe ATS 100 to the AGB 102.

The turbine housing 108 and the drive housing 122 can be formed by anyknown materials and methods, including, but not limited to, die-castingof high strength and lightweight metals such as aluminum, stainlesssteel, iron, or titanium. The turbine housing 108 and the drive housing122 defining the ATS 100 can be formed with a thickness sufficient toprovide adequate mechanical rigidity without adding unnecessary weightto the full assembly and, therefore, the aircraft.

The rotatable shaft 144 can be constructed by any known materials andmethods, including, but not limited to extrusion or machining of highstrength metal alloys such as those containing aluminum, iron, nickel,chromium, titanium, tungsten, vanadium, or molybdenum. The diameter ofthe turbine shaft 118 and drive shaft 134 along with any other shaftsdefining the rotatable shaft 144 can be fixed or vary along the lengthof the rotatable shaft 144. The diameter can vary to accommodatedifferent sizes, as well as rotor to stator spacings.

During operation air is introduced into the inlet 110, travels along theflow path 114 causing the rotation of the turbine member 116. Thisrotation enables the passing along of mechanical energy through therotatable shaft 144 to the AGB 102 and in turn to the engine 10 via thetransfer gear box 106 (FIG. 1 ). Upon starting the engine the clutch 142can disconnect the drive shaft 134 from the carrier member 131. In theevent of a backdrive, the ATS 100 should be disconnected from the AGB102. The decoupler assembly 148 enables a disconnection from the AGB102.

FIG. 3 is a schematic illustrating the LRC 150 according to an aspect ofthe disclosure herein. A valve 155 for controlling the passage oflubricant along the lubrication line 152 between the AGB 102 and the ATS100 can be disposed within the ATS 100. A distribution chamber 154 candefine at least a portion of the lubrication line 152. In onenon-limiting example the valve 155 is a multiplex control valve having afirst inlet 156 and a second inlet 158 for distributing lubricant and afirst return outlet 160 and a second return outlet 162 for re-directinglubricant.

The housing interior 140 can be further divided into the turbine sectioninterior 164 and the drive section interior 166. The turbine sectioninterior 164 can be at least partially defined by the turbine housing108 while the drive section interior 166 can be at least partiallydefined by the drive housing 122. The AGB 102 can include a lubricantreservoir 168. The lubricant reservoir 168 can be one reservoir, or bedivided into multiple reservoirs as illustrated, by way of non-limitingexample an oil supply 170 and an oil storage 172.

The lubrication line 152 can include a set of distribution conduits 174extending between the distribution chamber 154 and the housing interior140. The set of distribution conduits 174 can include a turbine conduit176 and a drive conduit 178. The turbine conduit 176 can extend betweenthe first inlet 156 and the turbine section interior 164. The turbineconduit 176 can define a turbine diameter (Dt). The drive conduit 178can extend between the second inlet 158 and the drive section interior166. The drive conduit 178 can define a drive diameter (Dd). Thelubrication line 152 can further include a set of connecting conduits180 extending between the lubricant reservoir 168 and the distributionchamber 154. The set of connecting conduits 180 can include a supplyline 182 and a return line 184. The supply line 182 can extend betweenthe oil supply 170 and the distribution chamber 154 and the return line184 can extend between the distribution chamber 154 and the oil storage172. The return line 184 can be fluidly coupled to the distributionchamber 154 via the first return outlet 160 or the second return outlet162.

The valve 155 can control a passage of lubricant (L) between thelubricant reservoir 168 and the housing interior 140. More specifically,in a turbine supply position 330 (see FIG. 5 ), the valve 155 can allowthe passage of lubricant (L) from the distribution chamber 154 to theturbine conduit 176 by opening the first inlet 156. Likewise, in a drivesupply position 340 (see FIG. 6 ), the valve 155 can allow the passageof lubricant (L) from the distribution chamber 154 to the drive conduit178 by opening the second inlet 158 to provide a reduced pressure flowrate to the drive section interior 166.

The valve 155 can open and close the first and second return outlets160, 162 to control the intake of lubricant (L) into the return line184. The first return outlet 160 can be open while in the drive supplyposition 340. In a bypass position 350 (see FIG. 7 ), the second returnoutlet 162 can be opened while the first and second inlets 156, 158 andthe first return outlet 160 are closed such that no lubricant (L) passesinto the housing interior 140. In this manner, the return line 184 candefine a portion of a bypass line 186 in both the drive supply position340 and the bypass position 350.The bypass line 186 includes thelubricant reservoir 168, the supply line 182, and the distributionchamber 154.

In one aspect of the disclosure, the valve 155 is a pressure valve thatis responsive to a lubricant pressure (P). The passage of lubricant (L)through the lubrication line 152 is controlled by the lubricant pressure(P) defined as a pressure on the lubricant (L) produced by a pressuredifference between the AGB 102 and the ATS 100. The lubricant pressure(P) in turn translates to a pressure on the valve 155. The lubricantpressure (P) can range between 15 psi and 50 psi (15 psi≤P≤50 psi). Insome implementations the range is between 20 psi and 45 psi (20 psi<P<45psi). At a low lubricant pressures, below 30 psi, the passage oflubricant (L) to the drive section interior 166 is closed while thepassage of lubricant (L) to the turbine section interior 164 is open. Ata high lubricant pressure, above 35 psi, the passage of lubricant (L) tothe drive section interior 166 is open while the passage of lubricant(L) to the turbine section interior 164 is closed. For ranges between 30psi and 35 psi, the valve 155 can be partially open for either/both theturbine conduit 176 or/and the drive conduit 178. 12.

In one aspect, higher lubricant pressure can result in a flow rate thatis more than necessary. In this case, the drive diameter (Dd) of thedrive conduit 178 can be formed to be smaller than the turbine diameter(Dt) to control the flow rate to the drive section interior 166. Whenthe drive diameter is less than the turbine diameter (Dd<Dt), the bypassline 186 can be opened to provide an outlet via the first return outlet160 for excess lubricant (L) to flow back to the lubricant reservoir168. It should be understood that the higher lubricant pressure (above35 psi) can cause a higher flow rate than necessary to the drive sectioninterior 166, in which case the bypass line 186 can be opened to providea lower flow rate, the drive diameter (Dd) can be decreased to provide alower flow rate, or a combination of both can be done to provide a lowerflow rate.

In an event where the ATS 100 develops a housing breach in one or bothof the turbine housing 108 or the drive housing 122, a sudden drop inthe pressure difference produces an increased lubricant pressure beyonda threshold pressure (P>50 psi). This sudden pressure increase can causethe valve 155 to close the first and second inlets 156, 158 and thefirst return outlet 160 and keep the second return outlet 162 open suchthat all lubricant (L) passes through the return line 184 back to thelubricant reservoir 168 and no lubricant (L) passes into the housinginterior 140. In other words, when the pressure difference between theATS 100 and the AGB 102 is indicative of a housing breach, the supplyline 182 is closed and the bypass line 186 is open, and, when thepressure difference is indicative of normal operation of the ATS 100,the supply line 182 is open.

Turning to FIG. 4 , a method 400 of supplying lubrication to an airturbine starter is illustrated in a flow chart. At a block 402,supplying the lubricant (L) to the ATS 100 from the AGB 102. At a block404, controlling the distribution of the lubricant (L) within the ATS100 with the valve 155. At a block 406, distributing the lubricant (L)to a first portion of the housing interior 140, by way of non-limitingexample one of the turbine section interior 164 or the drive sectioninterior 166, when the lubricant pressure (P) is within a given range.The given range can be between 20 psi and 35 psi or between 30 psi and45 psi. Distributing the lubricant (L) can include distributing thelubricant (L) to the turbine section interior 164 when the lubricantpressure (P) is below 35 psi. Distributing the lubricant (L) can alsoinclude distributing the lubricant (L) to the drive section interior 166when the lubricant pressure (P) is above 30 psi. Further, distributingthe lubricant (L) can include distributing the lubricant (L) to thereturn line 184 when the lubricant pressure (P) is above 30 psi.Further, distributing the lubricant (L) can include distributing thelubricant (L) to the return line 184 when the lubricant pressure (P) isabove 50 psi.

At block 408, the method 400 includes blocking the passage of lubricant(L) from the first portion of the housing interior 140 when thelubricant pressure (P) is greater than or less than the given range.Blocking the passage of lubricant (L) can include blocking the passageof lubricant (L) from the turbine section interior 164 when thelubricant pressure (P) is above 35 psi. Blocking the passage oflubricant (L) can include blocking the passage of lubricant (L) from thedrive section interior 166 when the lubricant pressure (P) is below 30psi. Blocking the passage of lubricant (L) can include blocking thepassage of lubricant (L) from both the turbine section interior 164 andthe drive section interior 166 when the lubricant pressure (P) is above50 psi.

Turning to FIG. 5 , a cross-section of taken along line V-V of FIG. 2illustrates an exemplary LRC 250 according to an aspect of thedisclosure herein. The LRC 250 is substantially similar to the LRC 150already described herein, therefore, like parts will be identified withlike numerals increased by 100. It should be understood that thedescription of the like parts of the LRC 150 applies to the LRC 250 ofFIG. 5 unless otherwise noted.

A lubrication line 252 extends from right to left in FIG. 5 , from theAGB 102 to the ATS 100. A distribution chamber 254 can define at least aportion of the lubrication line 252. The distribution chamber 254 can bedisposed within a wall 287 of the drive housing 122 for the ATS 100. Thedistribution chamber 254 can house a valve, by way of non-limitingexample a pressure valve 255. In one aspect, the pressure valve 255 canbe a sliding multiplex control valve comprising a piston 288 and astopper 290 disposed within a valve housing 291.

The lubrication line 252 can include a set of distribution conduits 274formed in the wall 287 and extending from the distribution chamber 254to fluidly couple the distribution chamber 254 to a housing interior, byway of non-limiting example the housing interior 140 (FIG. 3 ). The setof distribution conduits 274 can include a turbine conduit 276 and adrive conduit 278. The turbine conduit 276 can be fluidly coupled to thedistribution chamber 254 at a first inlet 256. The drive conduit 278 canbe fluidly coupled to the distribution chamber 254 at a second inlet258. The lubrication line 252 can further include a set of connectingconduits 280 fluidly coupling the lubricant reservoir 168 to thedistribution chamber 254. The set of connecting conduits 280 can includea supply line 282 and a return line 284. The return line 284 can befluidly coupled to the distribution chamber 254 at a first return outlet260 and a second return outlet 262.

The valve housing 291 can be located within the distribution chamber 254and extend between a closed end 292 at the wall 287 and an open end 293to define a valve centerline (CL). The open end 293 can be fluidlycoupled to the supply line 282. The valve housing 291 can include a setof openings, illustrated as a plurality of openings, a first opening294, a second opening 295, a third opening 296, and a fourth opening 297fluidly coupled to the first and second inlets 256, 258 and the firstand second return outlets 260, 262 respectively.

The piston 288 can have a substantially cylindrical shape, be locatedwithin the valve housing 291 and be movable in an axial direction withrespect to the valve centerline (CL) between a first position 298 and asecond position 299 (FIG. 6 ). The piston 288 can include piston walls300 defining a piston interior 301. An interior wall 302 extendingsubstantially perpendicular to the piston walls 300 can divide thepiston interior 301 into a first chamber 303 and a second chamber 304. Afirst spring 305 can be disposed in the first chamber 303, and a secondspring 306 different than the first spring 305 can be disposed in thesecond chamber 304. The second spring 306 can have a higher strength, orspring constant value (k), than the first spring 305. The first spring305 can have a strength set to enable the piston 288 to transposebetween the first and second positions 298, 299.

A set of thru holes, illustrated as a plurality of thru holes, a firstthru hole 314, a second thru hole 315, and a third thru hole 316can belocated within the piston walls 300. The first thru hole 314 extendsthrough the piston wall 300 from the second chamber 304 toward the valvehousing 291. The set of thru holes 314, 315, 316 can be selectivelyfluidly coupled to the set of openings 294, 295, 296, 297 of the valvehousing 291 and the inlets 256, 258 and outlets 260, 262.

The stopper 290 can extend between a first end 317 and a second end 318.Stopper walls 319 can define a hollow portion 320 within that defines atleast a portion of the lubrication line 252. The hollow portion 320 canextend between a stopper inlet 321 at the first end 317 and a firstoutlet 324 at the second end 318. The first outlet 324 can be fluidlycoupled to the first thru hole 314 of the piston 288. The hollow portion320 is fluidly coupled to the open end 293 of the valve housing 291 andin turn to the supply line 282 at the stopper inlet 321. A nose 322 canextend axially from the second end 318 along the valve centerline (CL)through the interior wall 302 of the piston 288. A set of side outlets,illustrated as a plurality of side outlets, a second outlet 325, and athird outlet 326 can be disposed within the stopper walls 319 toselectively fluidly couple the hollow portion 320 to the set of thruholes 314, 315, 316.

The stopper 290 can be movable in an axial direction with respect to thevalve centerline (CL) between a third position 327, a fourth position328 (in dashed line, FIG. 6 ) and a fifth position 329 (in dashed line,FIG. 7 ). The stopper 290 can move between the third and fourth position327, 328 with the piston 288 when the piston 288 moves between the firstand second positions 298, 299. The second spring 306 can have a strengthset to enable the stopper 290 to transpose between the fourth and fifthpositions 328, 329 at a certain pressure as the following describes.

A turbine supply position 330 occurs above a minimum pressurerequirement and below the high lubricant pressure where a force appliedto the first spring 305 and the second spring 306 by the lubricantpressure causes little to now compression of the springs 305, 306. Thefirst thru hole 314 of the piston 288 and the first opening 294 of thevalve housing 291 are aligned with the first inlet 256. In the turbinesupply position 330 the piston 288 is in the first position 298 and thestopper 290 is in the third position 327 as illustrated where thelubrication line 252 extends between the lubricant reservoir 168 and theturbine section interior 164. This opens a lubricant passageway from thehollow portion 320 to the turbine conduit 276, which in turn providesthe lubricant (L), by way of non-limiting example oil from the lubricantreservoir 168, in particular the oil supply 170, to the turbine sectioninterior 164.

Distributing the lubricant (L) to the turbine section interior 164 canoccur when the lubricant pressure (P) is above the minimum pressurerequirement, or above 10 psi and below the high lubricant pressure of 35psi. When the lubricant pressure (P) is between the minimum pressurerequirement and the high lubricant pressure, a pushing force is appliedon the first spring 305 from the interior wall 302. However, until thepressure reaches or surpasses a certain amount, by way of non-limitingexample the low lubricant pressure of 30 psi, the first spring 305compresses little to no amount at all. Therefore, below the lowlubricant pressure, the piston 288, remains in the first position 298until the pressure on the first spring 305 hits the certain amount.Between the low and high lubricant pressures, the piston 288 movestoward the second position 299 with the stopper 290 moving toward thefourth position 328 as the pressure increases and the first spring 305spring compresses. While the first spring 305 compresses, the lubricantpressure is not high enough to compress the second spring 306. Whileillustrated as fully open, it should be understood that the first inlet256 can be partially blocked as the first spring 305 moves.

In the turbine supply position 330, the second and third thru holes 315,316 are fluidly coupled to the second and third outlets 325, 326 in thestopper 290. However, in this position, while fluidly connected to eachother, the second and third thru holes 315, 316 and the second and thirdoutlets 325, 326 are blocked by the valve housing 291, as indicated bycircled x's 332, from being fluidly connected to the drive conduit 278and the return line 284 via the second and third openings 295, 296.

Turning to FIG. 6 , a drive supply position 340 is illustrated. Somenumbers have been removed for clarity only, the parts are the same asthose indicated in FIG. 5 . Between the low lubricant pressure and athreshold pressure value, the drive supply position 340 occurs. A forceis applied to the first spring 305 and the second spring 306. The forceis enough to compress the first spring 305 but not the second spring306. The compression causes the second thru hole 315 of the piston 288,the second opening 295 of the valve housing 291and the second outlet 325of the stopper 290 to align with the second inlet 258. In the drivesupply position 340, the piston 288 is in the second position 299 andthe stopper 290 has moved to the fourth position 328 with the piston288. In the drive supply position 340, the lubrication line 252 extendsbetween the lubricant reservoir 168 and the drive section interior 166.Further, the bypass line 186 is opened. In the drive supply position340, and the second thru hole 315, the second opening 295, and thesecond outlet 325 are fluidly coupled to the second inlet 258 of thedrive conduit 278. Further, in the drive supply position 340, the thirdthru hole 316, the third opening 296, and the third outlet 326 arealigned and fluidly coupled to the first return outlet 260 of the returnline 284.

As previously described herein, distributing the lubricant (L) to thedrive section interior 166 can occur when the lubricant pressure (P) isabove the low lubricant pressure of 30 psi. When the lubricant pressure(P) is above 30 psi, the pressure creates a pushing force on the firstspring 305 from the interior wall 302 causing the piston 288 to moveinto the second position 299. When the lubricant pressure (P) is abovethe high lubricant pressure of 35 psi, the piston 288 is fully in thesecond position 299. This opens a lubricant passageway from the hollowportion 320 to the drive conduit 278, which in turn provides thelubricant (L), by way of non-limiting example oil, from the lubricantreservoir 168, in particular the oil supply 170, to the drive sectioninterior 166. Due to the high lubricant pressure, this movement alsoopens a lubricant passageway from the hollow portion 320 to thelubricant reservoir 168, in particular the oil storage 172, via thebypass line 186. This in combination with the smaller diameterpreviously described herein provides a controlled flow to the drivesection interior 166.

Turning to FIG. 7 , a bypass position 350 is illustrated. Some numbershave been removed for clarity only, the parts are the same as thoseindicated in FIG. 5 . The bypass position 350 occurs at pressures at orabove the threshold pressure value, or 50 psi. At this pressure theforce is enough to compress the second spring 306 causing all fluidopenings to both the turbine conduit 276 and the drive conduit 278 toclose. The bypass position 350 is defined by when the piston 288 is inthe second position 299 and the stopper 290 is in the fifth position329. In the bypass position 350, the lubrication line 252 is definedsolely by the return line 284 defining the bypass line 286 which isopened. In the bypass position 350, the fourth opening 297 that iscoupled to the second return outlet 262 is open to the open end 293 ofthe valve housing 291. In the bypass position 350, no lubricant isprovided to the housing interior 140 (FIG. 2 ) of the ATS 100.

As previously described herein, blocking the passage of lubricant (L)from both the turbine section interior 164 and the drive sectioninterior 166 can occur when the lubricant pressure (P) is above thethreshold pressure, or 50 psi. When the lubricant pressure (P) is above50 psi, the pressure creates a pushing force on the second spring 306from the stopper 290 causing the second spring 306 to compress and thestopper 290 to move into the fifth position 329. This opens the bypassline 286 from the supply line 282 directly to the return line 284 andback to the lubricant reservoir 168, in particular the oil storage 172.

Turning to FIG. 8 , an enlarged view of section VIII from FIG. 2 isillustrated. A lubricant diverter 360 can be located within the drivehousing 122 to arrest the lubricant within the housing interior 140. Thelubricant diverter 360 can be mounted to the drive housing 122 by anysuitable fastener 362. The lubricant diverter 360 can include a diverterbody 364 shaped to move the lubricant (L) from a rotary motion (R) to anaxial direction (A). The diverter body 364 can extend both axially andcircumferentially (into the page) between a first end 366 at thefastener 362 to a second end 368. An outlet passage 370 can extendbetween the second end 368 and the set of outlets 153. A mesh 372 can beprovided at the set of AGB outlets 153 within the drive housing 122.During operation the lubricant diverter 360 enables a translation fromthe rotary motion (R) to the axial motion (A).

Turning to FIG. 9 , an enlarged view of section VIII from FIG. 2 isillustrated. A set of suction conduits 380 can be located within thedrive housing 122 having a hole axis along the rotary motion (R) of thelubricant (L). The set of suction conduits 380 include suction passages382 extending both axially and circumferentially (into the page) betweena suction inlet 384 and the set of outlets 153. During operation the setof suction conduits 380 enables a translation from the rotary motion (R)to the axial motion (A).

Turning to FIG. 10 , an enlarged view of section VIII from FIG. 2 isillustrated. A swirl diverter 390 can be located within the drivehousing 122 to arrest the lubricant within the housing interior 140. Theswirl diverter 390 can be mounted within the drive housing 122 proximatethe driven member 132. The swirl diverter 390 can include a swirl body392 shaped to move the lubricant (L) from a rotary motion (R) to anaxial direction (A). The swirl body 392 can extend both axially andcircumferentially (into the page). An outlet passage 394 can extendbetween the swirl body 392 and the set of outlets 153. During operationthe swirl diverter 390 enables a translation from the rotary motion (R)to the axial motion (A).

It should be understood that any of the lubricant diverter 360, thesuction conduits 380, or the swirl diverter 390 can be provided in theATS 100 described herein. It is further contemplated that aspects ofeach can be combined or provided within the ATS 100 at differentlocations.

All directional references (e.g., radial, upper, lower, upward,downward, left, right, lateral, front, back, top, bottom, above, below,vertical, horizontal, clockwise, counterclockwise) are only used foridentification purposes to aid the reader's understanding of thedisclosure, and do not create limitations, particularly as to theposition, orientation, or use thereof. Connection references (e.g.,attached, coupled, connected, and joined) are to be construed broadlyand can include intermediate members between a collection of elementsand relative movement between elements unless otherwise indicated. Assuch, connection references do not necessarily infer that two elementsare directly connected and in fixed relation to each other. Theexemplary drawings are for purposes of illustration only and thedimensions, positions, order and relative sizes reflected in thedrawings attached hereto can vary.

Many other possible embodiments and configurations in addition to thatshown in the above figures are contemplated by the present disclosure.Additionally, the design and placement of the various components such asstarter, AGB, or components thereof can be rearranged such that a numberof different in-line configurations could be realized.

The lubrication recirculation circuit described herein provides acommunication back and forth between the AGB and the air turbine starterof lubrication utilized in both areas. Since the lubricant, or in somecases oil pressure, is a function of the AGB shaft speed, the lubricantpressure will increase as the shaft speed increases. This change inpressure causes differentials in the lubricant pressure. Introducing thelubrication recirculation circuit as described herein enables a controlof the flow rate of lubricant, for example lubrication oil, to cool thebearing and rotating parts. At the lower pressures described herein, thelubricant will flow to the turbine section only during motoring and cutoff at the higher pressures discussed. At those higher pressures, thelubricant will flow to the drive section only during over running.Providing lubrication during extended motoring extends the life ofbearing and rotating parts of turbine section.

Benefits associated with the two springs described herein provideselective flow within the air turbine starter. Under normal workingconditions the springs activate according to the pressures therebyclosing the turbine and drive sections respectively when lubrication isnot necessary in either section. In other words, lubrication is providedto the respective locations within the air turbine starter whennecessary.

Further, a benefit of providing a pressure valve enables a complete shutoff of lubrication to the air turbine starter in case of a housingbreach causing the higher stiffness spring to activate. This in turncloses the flow path to the air turbine starter and the lubricant isbypassed to the AGB.

Further, to maintain proper levels of oil within the air turbinestarter, the flow set outlets described herein can be coupled to variousexemplary diverters. During drive shaft rotation, the lubricant will bein a swirling mode and the lubricant will not direct towards the set ofoutlets described which are oriented in a perpendicular direction withrespect to the swirling motion. Without diverters, the lubricant levelwithin the air turbine starter will increase. The diverters describedherein, the lubricant diverter, the set of suction outlets, and theswirl diverter, are provided in a swirling direction for the oil to passfrom the swirling or rotary motion to the axial direction and exit theair turbine starter.

To the extent not already described, the different features andstructures of the various embodiments can be used in combination, or insubstitution with each other as desired. That one feature is notillustrated in all of the embodiments is not meant to be construed thatit cannot be so illustrated, but is done for brevity of description.Thus, the various features of the different embodiments can be mixed andmatched as desired to form new embodiments, whether or not the newembodiments are expressly described. All combinations or permutations offeatures described herein are covered by this disclosure.

This written description uses examples to describe aspects of thedisclosure described herein, including the best mode, and also to enableany person skilled in the art to practice aspects of the disclosure,including making and using any devices or circuits and performing anyincorporated methods. The patentable scope of aspects of the disclosureis defined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral languages of the claims.

Further aspects are provided by the subject matter of the followingclauses:

An air turbine starter (ATS) for a gas turbine engine having anaccessory gear box (AGB) with a lubricant reservoir, the air turbinestarter comprising a housing at least partially defining a working airflow path; a turbine section comprising a turbine having a turbine shaftand a plurality of blades circumferentially spaced about the turbineshaft, the plurality of blades at least partially extending into theworking air flow path; a drive section having at least one lubricatedcomponent, a drive shaft operably coupling the turbine shaft to the AGB;and a lubrication recirculation circuit having a supply line fluidlycoupling the lubricant reservoir to the at least one lubricatedcomponent, and a return line fluidly coupling the at least onelubricated component to the lubricant reservoir.

The air turbine starter of any preceding clause further comprising abypass line fluidly coupling the supply line to the return line forbypassing the at least one lubricated component.

The air turbine starter of any preceding clause wherein the bypass linecomprises at least one return outlet fluidly coupling the supply line tothe return line.

The air turbine starter of any preceding clause further comprising avalve for controlling a flow of lubricant through the lubricationrecirculation circuit.

The air turbine starter of any preceding clause wherein the valve is apressure valve, which is responsive to a lubricant pressure.

The air turbine starter of any preceding clause wherein the at least onereturn outlet includes a first return outlet opened by the pressurevalve when the lubricant pressure is between a low lubricant pressureand a threshold pressure value to define a drive supply position.

The air turbine starter of any preceding clause wherein the supply lineis fluidly coupled to the drive section in the drive supply position.

The air turbine starter of any preceding clause wherein the at least onereturn outlet includes a second return outlet opened by the pressurevalve when the lubricant pressure is above a threshold pressure value todefine a bypass position.

The air turbine starter of any preceding clause wherein the supply lineis fluidly blocked from the drive section and the turbine section in thebypass position.

The air turbine starter of any preceding clause wherein the supply lineis fluidly coupled to the turbine section by the pressure valve when thelubricant pressure is between a minimum pressure requirement and a highlubricant pressure to define a turbine supply position.

The air turbine starter of any preceding clause further comprising apressure valve for controlling a flow of lubricant between the supplyline and the at least one lubricated component.

The air turbine starter of any preceding clause wherein the pressurevalve is a multiplex control valve which, when a pressure differencebetween the ATS and the AGB is indicative of a housing breach, thesupply line is closed and the bypass line is open, and, when thepressure in the pressure difference is indicative of normal operation ofthe ATS, the supply line is open.

The air turbine starter of any preceding clause further comprising apressure valve, which, when a pressure difference between the ATS andthe AGB is indicative of a housing breach, the supply line is closed,and, when the pressure difference is indicative of normal operation ofthe ATS, the supply line is open.

The air turbine starter of any preceding clause, further comprising afirst spring and a second spring with a different stiffness value thanthe first spring, the first spring transposing the pressure valvebetween a first position and a second position and the second springtransposing the pressure valve between a third position and a fourthposition.

A lubrication recirculation circuit comprising a lubricant reservoirlocated in an accessory gear box (AGB); a housing for an air turbinestarter (ATS), the housing defining an interior with at least onelubricated component, a turbine section with a turbine shaft, and adrive section with a drive shaft operably coupled to the turbine shaftlocated within, an output shaft at least partially disposed within thehousing and operably coupling the drive shaft to the AGB; and a supplyline fluidly coupling the lubricant reservoir to the at least onelubricated component, and a return line fluidly coupling the at leastone lubricated component to the lubricant reservoir.

The lubrication recirculation circuit of any preceding clause, furthercomprising a bypass line fluidly coupling the supply line to the returnline for bypassing the at least one lubricated component.

The lubrication recirculation circuit of any preceding clause whereinthe supply line comprises a set of distribution conduits including aturbine conduit fluidly coupled to the turbine section and a driveconduit fluidly coupled to the drive section.

The lubrication recirculation circuit of any preceding clause, furthercomprising a valve for selectively opening and closing the bypass line,the turbine conduit, and the drive conduit.

The lubrication recirculation circuit of any preceding clause, furthercomprising a first spring and a second spring with a different stiffnessvalue than the first spring, the first spring transposing the valvebetween a turbine supply position and a drive supply position and thesecond spring transposing the valve into a bypass position.

The lubrication recirculation circuit of any preceding clause, furthercomprising a set of outlets located in the housing and a diverter formoving a flow of lubricant from a rotary motion to an axial directionwith the diverter fluidly coupled to the set of outlets.

A lubrication recirculation circuit comprising a housing including atleast one opening; a set of distribution conduits having at least oneinlet fluidly coupled to the at least one opening; a piston disposedwithin the housing, movable between a first position and a secondposition, the piston having at least one thru hole fluidly coupled tothe at least one opening when the piston is in the first position; and astopper disposed within the piston, movable between a third position, afourth position, and a fifth position, the stopper having at least oneoutlet fluidly coupled to the at least one thru hole when the stopper isin the third position; a reservoir fluidly coupled to the at least oneoutlet; a lubrication line extending between the reservoir and the setof distribution conduits, the lubrication line open to a flow oflubricant when the piston is in the first position and closed to a flowof lubricant when the piston is in the second position.

The lubrication recirculation circuit of any preceding clause whereinthe at least one opening is multiple openings, the at least one inlet ismultiple inlets, the at least one thru hole is multiple thru holes, andthe at least one outlet is multiple outlets, wherein a first opening isfluidly coupled to a first inlet, a first outlet, and a first thru holewhen the piston is in the first position and the stopper is in the thirdposition, a second opening is fluidly coupled to a second inlet, asecond outlet, and a second thru hole when the piston is in the secondposition and the stopper is in the fourth position.

The lubrication recirculation circuit of any preceding clause wherein athird opening is fluidly coupled to a first return outlet, a thirdoutlet, and a third thru hole when the piston is in the second positionand the stopper is in the fourth position and a fourth opening isfluidly coupled a second return outlet when the piston is in the secondposition and the stopper is in the fifth position.

The lubrication recirculation circuit of any preceding clause whereinthe set of distribution conduits is multiple conduits including aturbine conduit extending between the first inlet and a turbine sectionand a drive conduit extending between the second inlet and a drivesection.

The lubrication recirculation circuit of any preceding clause furthercomprising a return line extending between a first return outlet and thereservoir and a bypass line extending between a second return outlet andthe reservoir.

1. An air turbine starter (ATS) for a gas turbine engine having anaccessory gear box (AGB) with a lubricant reservoir, the air turbinestarter comprising: a housing at least partially defining a working airflow path; a turbine section comprising a turbine having a turbine shaftand a plurality of blades circumferentially spaced about the turbineshaft, the plurality of blades at least partially extending into theworking air flow path; a drive section having at least one lubricatedcomponent, a drive shaft operably coupling the turbine shaft to the AGB;a lubrication recirculation circuit having a supply line fluidlycoupling the lubricant reservoir to the at least one lubricatedcomponent, and a return line fluidly coupling the at least onelubricated component to the lubricant reservoir; and a bypass linefluidly coupling the supply line to the return line for bypassing the atleast one lubricated component.
 2. (canceled)
 3. The air turbine starterof claim 1 wherein the bypass line comprises at least one return outletfluidly coupling the supply line to the return line.
 4. The air turbinestarter of claim 3 further comprising a valve for controlling a flow oflubricant through the lubrication recirculation circuit.
 5. The airturbine starter of claim 4 wherein the valve is a pressure valve, whichis responsive to a lubricant pressure.
 6. The air turbine starter ofclaim 5 wherein the at least one return outlet includes a first returnoutlet opened by the pressure valve when the lubricant pressure isbetween a low lubricant pressure value and a threshold pressure value todefine a drive supply position.
 7. The air turbine starter of claim 6wherein the supply line is fluidly coupled to the drive section in thedrive supply position.
 8. The air turbine starter of claim 5 wherein theat least one return outlet includes a second return outlet opened by thepressure valve when the lubricant pressure is above a threshold pressurevalue to define a bypass position.
 9. The air turbine starter of claim 8wherein the supply line is fluidly blocked from the drive section andthe turbine section in the bypass position.
 10. The air turbine starterof claim 5 wherein the supply line is fluidly coupled to the turbinesection by the pressure valve when the lubricant pressure is between aminimum pressure requirement and a high lubricant pressure value todefine a turbine supply position.
 11. The air turbine starter of claim 1further comprising a pressure valve for controlling a flow of lubricantbetween the supply line and the at least one lubricated component. 12.The air turbine starter of claim 11 wherein the pressure valve is amultiplex control valve which, when a pressure difference between theATS and the AGB is indicative of a housing breach, the supply line isclosed and the bypass line is open, and, when a pressure in the pressuredifference is indicative of normal operation of the ATS, the supply lineis open.
 13. The air turbine starter of claim 1 further comprising apressure valve, which, when a pressure difference between the ATS andthe AGB is indicative of a housing breach, the supply line is closed,and, when the pressure difference is indicative of normal operation ofthe ATS, the supply line is open.
 14. The air turbine starter of claim13, further comprising a first spring and a second spring with adifferent stiffness value than the first spring, the first springtransposing the pressure valve between a first position and a secondposition and the second spring transposing the pressure valve between afourth position and a fifth position.
 15. A lubrication recirculationcircuit comprising: a lubricant reservoir located in an accessory gearbox (AGB); a housing for an air turbine starter (ATS), the housingdefining an interior with at least one lubricated component, a turbinesection with a turbine shaft, and a drive section with a drive shaftoperably coupled to the turbine shaft located within, an output shaft atleast partially disposed within the housing and operably coupling thedrive shaft to the AGB; a supply line fluidly coupling the lubricantreservoir to the at least one lubricated component, and a return linefluidly coupling the at least one lubricated component to the lubricantreservoir: and a bypass line fluidly coupling the supply line to thereturn line for bypassing the at least one lubricated component. 16.(canceled)
 17. The lubrication recirculation circuit of claim 15 whereinthe supply line comprises a set of distribution conduits including aturbine conduit fluidly coupled to the turbine section and a driveconduit fluidly coupled to the drive section.
 18. The lubricationrecirculation circuit of claim 17, further comprising a valve forselectively opening and closing the bypass line, the turbine conduit,and the drive conduit.
 19. The lubrication recirculation circuit ofclaim 18, further comprising a first spring and a second spring with adifferent stiffness value than the first spring, the first springtransposing the valve between a turbine supply position and a drivesupply position and the second spring transposing the valve into abypass position.
 20. The lubrication recirculation circuit of claim 18,further comprising a set of outlets located in the housing and adiverter for moving a flow of lubricant from a rotary motion to an axialdirection with the diverter fluidly coupled to the set of outlets.